A Simple Approach to Assign Disulfide Connectivity Using Extracted Ion Chromatograms of Electron Transfer Dissociation Spectra

Increasing interest in production of protein-based pharmaceuticals (biotherapeutics) is accompanied by an increased need for verification of protein folding and correct disulfide bonding. Recombinant protein expression may produce aberrant disulfide bonds and could result in safety concerns or decreased efficacy. Thus, the thorough analysis of disulfide bonding is a necessity for protein therapeutics. The use of ETD facilitates this analysis because disulfide bonds are preferentially cleaved when subjected to ETD. Here, we make use of this well-characterized reaction to assign disulfide bonding networks by coupling the use of extracted ion chromatograms (XICs) of cysteine-containing peptides with ETD analysis to produce an efficient assignment approach for disulfide bonding. This method can be used to assign a disulfide pattern in a de novo fashion, to detect disulfide shuffling, and to provide information on heterogeneity, when more than one disulfide bonding pattern is present. The method was applied for assigning the disulfide-bonding network of a recombinant monomer of the HIV envelope protein gp120. It was found that one region of the protein, the V1/V2 loops, had significant heterogeneity in the disulfide bonds

Sedimentation Tanks for Treating Rainwater: CFD Simulations and PIV Experiments

The removal of solids is the most important step when treating rainwater. The article evaluates two designs of sedimentation tanks that can be used for the continuous separation of fine particles from water: OS—standard sedimentation tanks, and OW—swirl sedimentation tanks. The tanks were studied by conducting computational fluid dynamics (CFD) modeling and particle image velocimetry (PIV) experiments. The settling process in sedimentation tank was carried out at varying operating flow rates. A tank with a modified structure was used for the tests, where water was supplied by a nozzle placed at an angle. This solution made it possible to obtain a rotational flow that transported the suspended particles towards its wall, where downward axial velocity resulted in the settling of particles. Based on the research, it was observed that the flow patterns showed inward flow at the bottom of the tank and an upward flow and the lifting of the settled particles near the hatch at the bottom. The presented experimental measurements provided detailed insight into flow patterns, and valuable calibration and verification data for further CFD modeling. Traditional PIV techniques are useful in the case of standard design, whereas CFD is invaluable for supporting this work and for investigating the design of novel sedimentation tanks

Theoretical background of cylindricity profile evaluation of rotary parts by means of the bird-cage measuring method Part III: Calculation of the cylinder median line

W pracy zaproponowano algorytm wyznaczania linii środkowej walca zaobserwowanego metodą przekrojów wzdłużnych i metodą klatki pomiaru walcowości. W celu wyeliminowania wpływu składowych falistości zastosowano filtrację ocen punktów linii środkowej wykorzystującą podejście funkcjonałowe.The median line of a cylinder measured with the cross-section method is determined on the basis of the centre points of the mean circles of several subsequent cross-sections roundness profiles. Basically, the same principles could be used in the generatrix method. There may be, however, a large scatter of results due to a small number of measurement points with predetermined height coordinates and the occurrence of a waviness component in the cylindricity profile. The method for determination of the median line discussed in this paper involves filtering the measured points by applying the functional approach, as suggested by Krystek in Refs. [2, 3]. It is assumed that the coordinates of the measured median line points minimise the functional (13). One component of the functional assures appropriate approximation of the centres of the mean circles by means of the median line, and the other, termed the cost of curve bending, assures suitable smoothness of the median line eliminating the effect of the waviness components. A similar concept was employed in the bird-cage method, which is actually the combination of the cross-section and generatrix method. In this method, the median line points defined with the cross-section method are taken into account with appropriately greater weight than the points measured with the generatrix method (17). In the examples provided, the median line of a polished roller with a strong waviness component was determined for different cylindricity measurement methods

Computer-aided measurement of form profiles of cylindrical machine parts

Przedstawiono koncepcję skomputeryzowanych pomiarów zarysów kształtu walcowych części maszyn, polegającą na połączeniu przyrządu z komputerowym systemem przetwarzania sygnału. Opracowano program komputerowy ROFORM umożliwiający sterowanie procesem wykonywania pomiaru i kompleksową ocenę zmierzonych zarysów. Istotną zaletą tych pomiarów jest możliwość eliminowania niektórych systematycznych błędów, w tym eliminacji błędów wrzeciona, eliminacji błędów wywołanych pełzaniem sygnału pomiarowego oraz błędów wywołanych drganiami napędu wrzeciona.The paper is concerned with the concept of computer-aided measurements of form profiles of cylindrical machine parts, which involves connecting an instrument with a computer system of signal processing. The presented computer program, ROFORM, is applied to control the process of measurement and complex estimation of the measured profiles. A significant advantage of these measurements is the possibility to eliminate some of the systematic errors, such as spindle errors, errors caused by signal crawling, as well as those resulting from spindle drive vibrations